The redundant inner tie rod assembly protects against failure of a primary inner tie rod connection to the rack of a rack and pinion steering system.
The inner tie rod of a vehicle steering system is connected to a steering arm and to the rack of a rack and pinion steering system. The connection between the inner tie rod and the rack must accommodate pivotal movement about a plurality of axes. A ball and socket connection is therefore the preferred connection.
Ball and socket connections can fail occasionally. Failures, if they do occur, are generally due to lack of lubrication, extensive use over a period of years or excessive forces applied to the joint. Such failures may involve failure of the threads that hold either the ball or the socket in place, or failure of the inner tie rod housing crimp that holds the ball in the inner tie rod housing or socket. A worn or loose ball and socket as well as loose threads can be identified by excess play in the steering wheel when the ball and socket are part of a front wheel steering system. Detection of a worn ball and socket or loose thread connections in a rear wheel steering system of a vehicle with four wheel steering is more difficult. Looseness in a rear wheel steering system, indicating that the threads or the housing crimp that hold a ball in the housing need to be inspected or repaired, may not be detectable by turning the steering wheel.
The front steered wheels of a vehicle have a steering geometry that includes caster, camber and toe in. This geometry tends to turn the steered front wheels to a position that directs a vehicle straight forward if the operator releases the steering wheel or if there is a steering linkage failure.
The rear wheels of a vehicle with four wheel steering generally have negative caster. A failure in the steering linkage of the rear wheels of a vehicle may therefore make the vehicle unstable.
A vehicle has a body supported by front steered wheels and rear steered wheels. A rear rack and pinion steering system having a rack driven by a pinion. A first inner tie rod transmits steering forces from the rack to one of the rear steered wheels. The first inner tie rod is connected to the rack by a primary inner tie rod connector as well as by a redundant inner tie rod connector.
The redundant inner tie rod assembly includes a steering rack and pinion housing. A steering rack is supported in the steering rack housing for axial movement relative to the rack and pinion housing. A steering rack first end extends out of the rack and pinion housing. An inner support nut is fixed to the steering rack first end. An inner tie rod has a tie rod inner end. An inner tie rod housing receives an inner end ball that is retained in the inner tie rod housing and is pivotable relative to the inner tie rod housing. The inner end ball and the inner tie rod housing interconnect the steering rack first end and the tie rod inner end. An inner support clamp with a central passage telescopically receives the inner tie rod. A clamp outer flange is mechanically connected to the inner support nut and limits separation of the inner tie rod end from the steering rack first end.